Disclosed is a building panel curved along both major and minor axes and relates to the building industry in general and the boat building field in particular.
As is known in the boat building, aircraft and other industries, it is extremely difficult to provide panels with curvatures in both the major and minor axes (compound and complex being the most common of such curved surfaces). It has long been known that a compound curved wooden surface can be made by the process of "cold-molding" which consists in fitting together a plurality of small strips of flat building material in order to produce a larger surface which is curved in one or more directions.
In order to achieve maximum strength, it is desirable to have as close a fit as possible between adjacent edges of the fitted strips. In the past the close fit between strips is achieved by hand carving the edges of each strip resulting in a unique geometric shape for each strip depending on the curve of the surface desired. In the boat building field this custom-fitting process is known as "spiling" and the labor involved is very expensive. Consequently, because of the time, skill and cost of this operation, mass production of panels having compound or complex curvatures is extremely challenging and necessarily expensive. Further complicating prior art "cold-molding" techniques is the problem of bi-lateral structures: for example the starboard half and port half of a two-piece boat hull. Because these hull sections are the mirror image of each other, separate molds jigs, frames etc. are necessary in constructing the two hull sections. The fact that parts used in producing the port section cannot be used to form the starboard section, doubles the material necessary and consequently raises the cost of hull construction.
A more complete appreciation of the difficulties in providing a surface curved in two directions with respect to water vessels may be had by reference to U.S. Pat. No. 2,235,601 which acknowledges that each plank must be "planed to final shape" in order to fit with the other planks forming the hull section.
Thus it will be readily understood that there is a long felt need for a practical method for producing building panels curved in two directions from a basically flat planar material. There is a need to overcome the necessity for individual hand carving of multiple planks in order to fit the two-dimensional material into the desired multiply curved final shape. It is clear that should a method be provided for the inexpensive manufacture of such curved panels, there are numerous applications which, although previously were not economically viable, would become feasible.